﻿#region LicenseHeader

// Copyright 2012 The Trustees of Indiana University.  All rights reserved.
// 
// The Indiana University licenses this file to you under the Apache License, 
// Version 2.0 (the "License"); you may not use this file except in compliance 
// with the License.  You may obtain a copy of the License at 
// 
// http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software 
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
//  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  
// See the License for the specific language governing permissions and 
// limitations under the License.
// 
// @author Thilina Gunarathne (tgunarat@indiana.edu)

#endregion

#region

using System;
using System.Collections.Generic;
using System.IO;
using System.Runtime.CompilerServices;
using AzureMRCore.DataTypes;
using AzureMRCore.Primitives;

#endregion

namespace AzureMRCore.InputFormat
{
    public class CachedLineInputFormat : IInputFormat<IntKey, StringValue>, ICachedInputFormat
    {
        private int counter;
        private string currentLine;
        private Boolean isDeffering = true;
        private List<string> lines;
        private StreamReader reader;
        private long size;

        #region ICachedInputFormat Members

        public long GetSize()
        {
            return size;
        }

        public ICachedInputFormat GetCachedCopy()
        {
            readAll();
            CachedLineInputFormat newCachedFormat = new CachedLineInputFormat();
            newCachedFormat.Init(lines, size);
            return newCachedFormat;
        }

        #endregion

        #region IInputFormat<IntKey,StringValue> Members

        public void Init(string inputFile)
        {
            reader = new StreamReader(inputFile);
            FileInfo file = new FileInfo(inputFile);
            size = file.Length;
            lines = new List<string>();
        }

        public IntKey GetCurrentKey()
        {
            IntKey intKey = new IntKey {Key = counter};
            return intKey;
        }

        public StringValue GetCurrentValue()
        {
            StringValue value = new StringValue {Value = currentLine};
            return value;
        }

        [MethodImpl(MethodImplOptions.Synchronized)]
        public bool Next()
        {
            if (isDeffering)
            {
                string line = reader.ReadLine();
                if (line != null)
                {
                    currentLine = line;
                    lines.Add(line);
                    counter++;
                    return true;
                }
                return false;
            }
            else
            {
                if (counter < lines.Count)
                {
                    currentLine = lines[counter];
                    counter++;
                    return true;
                }
                else return false;
            }
        }

        [MethodImpl(MethodImplOptions.Synchronized)]
        public bool HasNext()
        {
            if (isDeffering)
            {
                return !(reader.EndOfStream);
            }
            else
            {
                return (lines.Count > counter);
            }
        }

        [MethodImpl(MethodImplOptions.Synchronized)]
        public void Close()
        {
            if (isDeffering)
            {
                readAll();
                reader.Close();
                isDeffering = false;
            }
        }

        public List<KeyValuePair<IntKey, StringValue>> GetAllPairs()
        {
            throw new NotImplementedException();
        }

        #endregion

        public void Init(IDictionary<int, BCastDataProduct> inputRecords)
        {
            throw new NotImplementedException();
        }

        public void Init(List<string> lines, long size)
        {
            this.lines = lines;
            this.size = size;
            isDeffering = false;
        }

        [MethodImpl(MethodImplOptions.Synchronized)]
        private void readAll()
        {
            if (!isDeffering) return;
            string line = reader.ReadLine();
            while ((line = reader.ReadLine()) != null)
            {
                lines.Add(line);
            }
            isDeffering = false;
        }
    }
}